drivers/pwm/pwm-rockchip.c

   1 /*
   2  * PWM driver for Rockchip SoCs
   3  *
   4  * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
   5  * Copyright (C) 2014 ROCKCHIP, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * version 2 as published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/of_device.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/pwm.h>
  19 #include <linux/time.h>
  20
  21 #define PWM_CTRL_TIMER_EN       (1 << 0)
  22 #define PWM_CTRL_OUTPUT_EN      (1 << 3)
  23
  24 #define PWM_ENABLE              (1 << 0)
  25 #define PWM_CONTINUOUS          (1 << 1)
  26 #define PWM_DUTY_POSITIVE       (1 << 3)
  27 #define PWM_INACTIVE_NEGATIVE   (0 << 4)
  28 #define PWM_OUTPUT_LEFT         (0 << 5)
  29 #define PWM_LP_DISABLE          (0 << 8)
  30
  31 struct rockchip_pwm_chip {
  32         struct pwm_chip chip;
  33         struct clk *clk;
  34         const struct rockchip_pwm_data *data;
  35         void __iomem *base;
  36 };
  37
  38 struct rockchip_pwm_regs {
  39         unsigned long duty;
  40         unsigned long period;
  41         unsigned long cntr;
  42         unsigned long ctrl;
  43 };
  44
  45 struct rockchip_pwm_data {
  46         struct rockchip_pwm_regs regs;
  47         unsigned int prescaler;
  48
  49         void (*set_enable)(struct pwm_chip *chip, bool enable);
  50 };
  51
  52 static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
  53 {
  54         return container_of(c, struct rockchip_pwm_chip, chip);
  55 }
  56
  57 static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip, bool enable)
  58 {
  59         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
  60         u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
  61         u32 val;
  62
  63         val = readl_relaxed(pc->base + pc->data->regs.ctrl);
  64
  65         if (enable)
  66                 val |= enable_conf;
  67         else
  68                 val &= ~enable_conf;
  69
  70         writel_relaxed(val, pc->base + pc->data->regs.ctrl);
  71 }
  72
  73 static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip, bool enable)
  74 {
  75         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
  76         u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
  77                           PWM_CONTINUOUS | PWM_DUTY_POSITIVE |
  78                           PWM_INACTIVE_NEGATIVE;
  79         u32 val;
  80
  81         val = readl_relaxed(pc->base + pc->data->regs.ctrl);
  82
  83         if (enable)
  84                 val |= enable_conf;
  85         else
  86                 val &= ~enable_conf;
  87
  88         writel_relaxed(val, pc->base + pc->data->regs.ctrl);
  89 }
  90
  91 static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  92                                int duty_ns, int period_ns)
  93 {
  94         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
  95         unsigned long period, duty;
  96         u64 clk_rate, div;
  97         int ret;
  98
  99         clk_rate = clk_get_rate(pc->clk);
 100
 101         /*
 102          * Since period and duty cycle registers have a width of 32
 103          * bits, every possible input period can be obtained using the
 104          * default prescaler value for all practical clock rate values.
 105          */
 106         div = clk_rate * period_ns;
 107         do_div(div, pc->data->prescaler * NSEC_PER_SEC);
 108         period = div;
 109
 110         div = clk_rate * duty_ns;
 111         do_div(div, pc->data->prescaler * NSEC_PER_SEC);
 112         duty = div;
 113
 114         ret = clk_enable(pc->clk);
 115         if (ret)
 116                 return ret;
 117
 118         writel(period, pc->base + pc->data->regs.period);
 119         writel(duty, pc->base + pc->data->regs.duty);
 120         writel(0, pc->base + pc->data->regs.cntr);
 121
 122         clk_disable(pc->clk);
 123
 124         return 0;
 125 }
 126
 127 static int rockchip_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 128 {
 129         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 130         int ret;
 131
 132         ret = clk_enable(pc->clk);
 133         if (ret)
 134                 return ret;
 135
 136         pc->data->set_enable(chip, true);
 137
 138         return 0;
 139 }
 140
 141 static void rockchip_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 142 {
 143         struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
 144
 145         pc->data->set_enable(chip, false);
 146
 147         clk_disable(pc->clk);
 148 }
 149
 150 static const struct pwm_ops rockchip_pwm_ops = {
 151         .config = rockchip_pwm_config,
 152         .enable = rockchip_pwm_enable,
 153         .disable = rockchip_pwm_disable,
 154         .owner = THIS_MODULE,
 155 };
 156
 157 static const struct rockchip_pwm_data pwm_data_v1 = {
 158         .regs = {
 159                 .duty = 0x04,
 160                 .period = 0x08,
 161                 .cntr = 0x00,
 162                 .ctrl = 0x0c,
 163         },
 164         .prescaler = 2,
 165         .set_enable = rockchip_pwm_set_enable_v1,
 166 };
 167
 168 static const struct rockchip_pwm_data pwm_data_v2 = {
 169         .regs = {
 170                 .duty = 0x08,
 171                 .period = 0x04,
 172                 .cntr = 0x00,
 173                 .ctrl = 0x0c,
 174         },
 175         .prescaler = 1,
 176         .set_enable = rockchip_pwm_set_enable_v2,
 177 };
 178
 179 static const struct rockchip_pwm_data pwm_data_vop = {
 180         .regs = {
 181                 .duty = 0x08,
 182                 .period = 0x04,
 183                 .cntr = 0x0c,
 184                 .ctrl = 0x00,
 185         },
 186         .prescaler = 1,
 187         .set_enable = rockchip_pwm_set_enable_v2,
 188 };
 189
 190 static const struct of_device_id rockchip_pwm_dt_ids[] = {
 191         { .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
 192         { .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
 193         { .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
 194         { /* sentinel */ }
 195 };
 196 MODULE_DEVICE_TABLE(of, rockchip_pwm_dt_ids);
 197
 198 static int rockchip_pwm_probe(struct platform_device *pdev)
 199 {
 200         const struct of_device_id *id;
 201         struct rockchip_pwm_chip *pc;
 202         struct resource *r;
 203         int ret;
 204
 205         id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
 206         if (!id)
 207                 return -EINVAL;
 208
 209         pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
 210         if (!pc)
 211                 return -ENOMEM;
 212
 213         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 214         pc->base = devm_ioremap_resource(&pdev->dev, r);
 215         if (IS_ERR(pc->base))
 216                 return PTR_ERR(pc->base);
 217
 218         pc->clk = devm_clk_get(&pdev->dev, NULL);
 219         if (IS_ERR(pc->clk))
 220                 return PTR_ERR(pc->clk);
 221
 222         ret = clk_prepare(pc->clk);
 223         if (ret)
 224                 return ret;
 225
 226         platform_set_drvdata(pdev, pc);
 227
 228         pc->data = id->data;
 229         pc->chip.dev = &pdev->dev;
 230         pc->chip.ops = &rockchip_pwm_ops;
 231         pc->chip.base = -1;
 232         pc->chip.npwm = 1;
 233
 234         ret = pwmchip_add(&pc->chip);
 235         if (ret < 0) {
 236                 clk_unprepare(pc->clk);
 237                 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 238         }
 239
 240         return ret;
 241 }
 242
 243 static int rockchip_pwm_remove(struct platform_device *pdev)
 244 {
 245         struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev);
 246
 247         clk_unprepare(pc->clk);
 248
 249         return pwmchip_remove(&pc->chip);
 250 }
 251
 252 static struct platform_driver rockchip_pwm_driver = {
 253         .driver = {
 254                 .name = "rockchip-pwm",
 255                 .of_match_table = rockchip_pwm_dt_ids,
 256         },
 257         .probe = rockchip_pwm_probe,
 258         .remove = rockchip_pwm_remove,
 259 };
 260 module_platform_driver(rockchip_pwm_driver);
 261
 262 MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
 263 MODULE_DESCRIPTION("Rockchip SoC PWM driver");
 264 MODULE_LICENSE("GPL v2");